The present disclosure relates to a percussion boring system and, more particularly, to an improved drill bit assembly for a percussion boring system.
One having ordinary skill in the art knows that percussion boring systems are capable of directionally boring a winding channel in a substrate. These channels are commonly bored for any number of purposes such as for holding a product in the form of a conductive conduit, a fiber optic cable, a stretch of tubing, etc.
Percussion boring a subterranean channel for holding a product usually begins by boring a pilot-channel in a substrate along a substantially predetermined path. The pilot-channel has an entry point, where the leading end of the percussion boring system initially entered the substrate, and an exit point, where the leading end of the percussion boring system eventually emerged from the substrate. Notably, because operators of percussion boring systems are often allowed very little deviation from the approved subterranean path and exit point location, an accurately set-up and calibrated percussion boring system is desirable. Current systems used in the art, however, can be tedious to calibrate during set-up, thereby causing unnecessary delay and cost during set-up and resulting in a less than optimum calibration that makes staying on the predetermined subterranean path difficult. Therefore, there is a need in the art for a percussion boring system that provides for efficient set-up and accurate calibration.
Once emerged from the pilot-bore at the exit point, a percussion boring system may be modified to pull a product back through the bore it just drilled. For percussion boring systems known in the art, modifying the system so that it can pull an attached product back through the bore often entails replacing a drill bit with a back reaming device, i.e. a back reamer. The back reamer may be sized to increase the cross-sectional area of the pilot-bore and condition its walls as the entire drill string is retracted and a product attached to the back reamer is pulled into place. Notably, removing the drill bit and installing the back reamer so that product may be pulled into the bore can be time consuming and expensive to accomplish in the field. Therefore, there is a need in the art for a percussion boring system that may be easily converted from a pilot-boring configuration to a product-pulling configuration without having to remove the drill bit.